Objective: For women in many parts of the world, the behavior that puts them at greatest risk for HIV infection is unprotected sex within marriage. The proposed comparative ethnographic study will explore how social and cultural factors influence marital and extramarital intimate relationships and examine the sexual and the HIV prevention practices of men and women engaged in building these relationships across five locations in countries at different stages of the HIV epidemic. By detailing the processes through which contextual factors shape women's risk of marital HIV infection, this study will contribute to our understanding of ways to reduce the risk of heterosexual HIV transmission. Background and Significance: The study is guided by three premises: that the role of married men in sustaining heterosexual transmission of HIV has been insufficiently explored; that spreading ideologies of monogamous companionate marriage may put married women at particular risk, and that culturally specific knowledge about the social, economic, and emotional context of sexual relationships can provide important insight into the avenues through which gender inequality combines with economic organization and emerging ideologies of marital love to put women at risk for marital HIV transmission. Methods: Five developing country sites representing different stages of the HIV epidemic have been selected for study: Degollado, Jalisco Tari, Papua New Guinea, Soc Son, Vietnam, Ubakala, Nigeria, and Bulubandi, Uganda. In each site, researchers will use ethnographic methods to examine the social and cultural determinants of the risk of marital transmission of HIV. We anticipate totals of 200 semi-structured ethnographic interviews with a systematic ethnographic sample of men and women (40 per site) and 100 marital case histories (20 per site), to be collected over 6 months of participant observation. For each field site, ethnographic data will be analyzed using a multilevel hierarchical coding process to relate specific attitudes and behaviors to relationship- and macro-level factors. The ethnographic findings will be pooled to conduct an analysis of key themes and findings across sites. Implications: The assumption that marriage equals monogamy may be costing women their lives. Data from this project will be used to trace the social and ideological contexts within which men and women build sexual relationships and become exposed to HIV risk and to develop proposals for culturally appropriate, gender-sensitive interventions to reduce this risk. [unreadable] [unreadable]